Paper mixing preventing apparatus

ABSTRACT

Disclosed is a paper mixing preventing apparatus which prevents a paper sheet stacked on a paper buffering unit, a paper arranging unit, or a stacker tray on a paper feeing path and a succeeding feeding sheet from being out of sequence. A lower unit and an upper unit are installed between a stacked paper sheet and the succeeding paper sheet. A pressing plate of the upper unit and the support plate of the lower unit move, so the support plate of the lower unit is rotated together with the pressing plate to prevent the succeeding paper sheet from being damaged. The associated movements of the lower unit and the upper unit are released at a position where the pressing plate of the upper unit is moved, and the lower unit primarily returns to its initial state and the upper unit returns to its initial state subsequently.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a paper mixing preventing apparatus for a paper finishing apparatus installed in an image forming apparatus, such as a printer and a printer, which is adapted to prevent two or more paper sheets from being out of sequence when they are discharged to a paper stacking unit such as a paper arranging unit, a paper buffering unit, and a stacker tray.

2. Description of the Related Art

In general, paper sheets which have been processed in an image forming apparatus, such as a copy machine, are discharged to a paper buffering unit, a paper arranging unit, or a stacker tray through a paper discharging apparatus.

The paper sheets discharged to the paper buffering unit, the paper arranging unit, or the stacker tray through the paper discharging apparatus tends to deflect into an arc shape due to the internal heats of the units. In this case, when the paper sheets deflected into an arc shape are buffered or stacked on the stacker tray, the paper sheets may be warped or delaminated, so that a succeeding paper sheet may be fed beneath a preceding paper sheet out of the sequence, and a paper arranging error may occur in the paper arranging unit.

It does not matter even if the paper sheets are stacked out of the sequence if the paper sheets have no page order. However, if the paper sheets are needed to be stacked in the sequence of page order, a binding error may be generated when the paper sheets are stacked out of sequence.

SUMMARY

The present invention has been made to solve the problems occurring in the prior art, and the present invention provides a paper mixing preventing apparatus, in which a lower unit and an upper unit through which a succeeding paper sheet passes are installed between buffered or stacked paper sheets and the succeeding paper sheet so that a rear end of the stacked paper sheet may be located at least behind a tip end of a support plate of the lower unit in an initial state of the lower unit. When the succeeding paper sheet is stacked, a pressing plate of the upper unit and the support plate of the lower unit move in association with each other, so the support plate of the lower unit is rotated together with the pressing plate of the upper unit to prevent a rear end of the succeeding paper sheet, which is being stacked during the downward rotation of the pressing plate. The associated movements of the lower unit and the upper unit are released at a position where the pressing plate of the upper unit is moved after it is rotated by a predetermined angle, pressing the rear end of the succeeding paper sheet, and the lower unit primarily returns to its initial state and the upper unit returns to its initial state subsequently.

It is an object of the present invention to provide a paper mixing preventing apparatus which prevents a paper sheet buffered on a paper feeding path or stacked on a stacker tray and a succeeding paper sheet from being out of sequence, arranging paper sheets efficiently.

It is another object of the present invention to provide a paper mixing preventing apparatus which has enhanced reliability and stability with a simple structure.

In order to accomplish the above object, the present invention provides a paper mixing preventing apparatus including a lower unit including a first shaft, a support plate fixed to the first shaft, and a lever supported by at least one end of the first shaft and configured to move in association with a rotation direction of the first shaft; and an upper unit including a second shaft installed parallel to the first shaft, a pressing plate fixed to the second shaft and disposed on a side facing the support plate of the lower unit, and a lever pushing member installed in the pressing plate.

The support plate of the lower unit is rotated about the first shaft by a predetermined angle by a contact between the lever pushing member and the lever when the pressing plate of the upper unit is rotated about the second shaft, and the contact between the lever of the lower unit and the lever pushing member of the upper unit is released if the pressing plate of the upper unit is rotated by more than a predetermined angle so that the upper unit returns to an initial state thereof after the lower unit primarily returns to an initial state thereof.

One of a paper buffering unit, a paper arranging unit, and a stacker tray is installed under the lower unit.

The lever of the lower unit is movably supported in a central axis direction of the first shaft, and the lever pushing member makes contact with a side surface of the lever of the lower unit and returns to an initial state thereof while pushing the side surface of the lever when the upper unit returns to an initial state thereof.

The lever pushing member and the side surface of the lever are inclined with respect to each other.

A lower surface of the lever pushing member makes contact with an upper surface of the lever when the lever pushing member is located at an upper portion of the lever, and the inclined surface of the lever pushing member and the inclined surface of the lever make contact with each other when the lever pushing member is located at a lower portion of the lever.

The lever is resiliently supported by a resilient member so as to be movable in a central axis direction of the first axis.

A paper detecting sensor is installed on a rear side of the lower unit to detect a paper sheet being fed, the upper unit is driven by a signal of the paper detecting sensor, the pressing plate of the upper unit presses a rear end of the paper sheet being fed and the support plate of the lower unit is rotated in association with the pressing operation of the pressing plate so as not to interfere with the pressing operation of the pressing plate with respect to the rear end of the paper sheet.

The lower unit returns to an initial state by a resilient member.

The resilient member is a spring.

The paper mixing preventing apparatus according to the present invention is installed at a paper entering position of a paper buffering unit, a paper arranging unit, or a stacker tray where a paper sheet is temporarily stacked on a paper feeding path. A lower unit and an upper unit are installed to pass a paper sheet therethrough. When a paper sheet is stacked on the stacker tray, a pressing plate of the upper unit and a support plate of the lower unit move in association with each other to press a rear end of the paper with the pressing plate of the upper unit so that the support plate of the lower unit cannot hamper the paper sheet when it is pressed. Thus, the support plate of the lower unit may not interfere with the paper sheet, thereby preventing damage to the paper sheet. Also, the paper sheet stacked on the paper buffering unit, the paper arranging unit, or the stacker tray is stacked such that the rear end of the paper sheet is located at least on the rear side of a tip end of the support plate of the lower unit with respect to an initial position of the lower unit, thereby making it possible to basically prevent the paper sheet and a succeeding paper sheet from being out of sequence when they are stacked.

Furthermore, when the paper mixing preventing apparatus is applied to a paper arranging unit, since a rear end of a deflected paper sheet is pressed, paper arranging performance can be enhanced when paper sheets are arranged.

In addition, reliability in discharging papers and stability can be improved without making the structure of the apparatus complex.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view of a paper mixing preventing apparatus according to the present invention;

FIG. 2 is a side view of FIG. 1;

FIG. 3 is a perspective view illustrating a state where a pressing plate of an upper unit and a support plate of a lower unit of the paper mixing preventing apparatus according to the present invention are operated;

FIG. 4 is a side view of FIG. 3;

FIG. 5 is a perspective view illustrating a state where the support plate of the lower unit has returned to its original position and the pressing plate of the upper unit has not returned to its original position in the paper mixing preventing apparatus according to the present invention;

FIG. 6 is a side view of FIG. 5;

FIG. 7 is a perspective view illustrating a state where a lever pushing member of the upper unit contacts a side surface of a lever of the lower unit to push the lever to the outside while the pressing plate of the upper unit is returning to its original position in the paper mixing preventing apparatus according to the present invention;

FIG. 8 is a plan view of FIG. 7;

FIGS. 9A to 9E are views illustrating the operations of the upper unit and the lower unit of the paper mixing preventing apparatus according to the present invention;

FIG. 10 is a sectional view illustrating a state where a side surface of the lever pushing member of the upper unit slantingly makes contact with a side surface of the lever of the lower unit in the paper mixing preventing apparatus according to the present invention; and

FIGS. 11A to 11E are views for explaining the operations of the paper mixing preventing apparatus according to the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, the configuration and operation of the present invention will be described with reference to FIGS. 1 to 8.

A paper mixing preventing apparatus 10 according to the present invention may be usefully installed on a paper feeding path, for example, at an entrance of a paper buffering unit (not shown), or at an entrance of a paper arranging unit (not shown) or a stacker tray to preventing paper sheets from being out of sequence, and is installed at an entrance of a stacker tray 400 on the paper feeding path in this example.

Thus, it should be noted that the paper mixing preventing apparatus 100 of the present invention may be installed on a feeding path at any location where two or more paper sheets are temporarily stacked as well as at an entrance of the stacker tray 400.

The paper mixing preventing apparatus 100 of the present invention includes a lower unit 200 and an upper unit 300 as illustrated in FIGS. 1 and 2.

First, the lower unit 200 includes a first shaft formed to cross an upper end of the stacker tray 400, a support plate 202 fixed to the first shaft 201 in a wing-like shape and disposed to face a bottom surface of the stacker tray 400, and a lever 203 fixed to one end of the first shaft 201. The support plate 202 is disposed such that the back of the support plate 202 is directed toward a direction along which the paper sheets are fed. The lever 203 serves as leverage for rotating an end of the support plate 202 toward a bottom surface of the stacker tray 400, and is fixed to the first shaft 201.

The lever 203 is fixed to the first shaft 201 to be moved in association with the first shaft 201, and is resiliently supported by a spring 205 while being able to move about the central axis of the first shaft 201. The lever 203 has an inclined surface 203 which is tapered as shown in FIG. 10.

Rotation of the first shaft 201 is restricted by a stopper (not shown) so that the support plate 202 may not be rotated toward the upper side from a position which is slantingly moved downward from a feeding paper guide surface 501, and a spring 206 is installed to prevent the support plate 202 from moving downward from the stopped position due to gravity.

Meanwhile, the upper unit 300 includes a second shaft 301 installed parallel to the first shaft 201 of the lower unit 200, a pushing plate 302 fixed to the second shaft 301 and disposed to face the support plate 202 of the lower unit 200, and a lever pushing member 303 installed at a periphery of the pushing plate 302. An inclined surface 303 a facing the inclined surface 203 a of the lever 203 is formed on one side surface of the lever pushing member 303.

The inclined surface 303 a of the lever pushing member 303 is formed such that the diameter of a lower surface of the lever pushing member 203 is larger than the diameter of an upper surface thereof as in FIG. 10, so that the lever pushing member 303 pushes an end of the lever 203 and rotates the support plate 202 when it moves downward from its initial state and easily pushes a side surface of the lever 203 while it is returning to its original position after the support plate 202 and the lever 203 have returned to its initial position. On the other hand, the inclined surface 203 a is formed in the lever 203 such that the diameter of a lower surface of the lever 203 is smaller than the diameter of an upper surface thereof.

The pushing plate 302 is located on the upper side of the support plate 202 of the lower unit 200 so that a paper sheet fed between a pair of rollers 502 is guided by the support plate 202 and the pushing plate 302 and is discharged to the stacker tray 400.

The second shaft 301 to which the pressing plate 302 is fixed is rotated forwardly or reversely by a predetermined angle using a drive motor 305 to which a gear 304 is mounted. The rotation angle of the second shaft 301 to which the pressing plate 302 is fixed is regulated by at least one pressing plate position detecting sensor 306.

A pair of rollers 503 and a paper detecting sensor 503 is installed in front of the upper unit 300 and the lower unit 200, i.e. on a paper guide surface 501

FIGS. 3 and 4 illustrate a state where the pressing plate 302 and the support plate 202 simultaneously move downward in association with each other toward a bottom surface of the stacker tray 400 when the drive motor 305 is driven and the lever pushing member 303 presses the lever 203.

FIGS. 5 and 6 illustrate a state where the contact between the lever pushing member 303 and the lever 203 is released and the support plate 202 and the lever 203 return to their initial states due to the operation of the spring 206 when the pressing plate 302 is rotated downward to a position detected by the pressing plate position detecting sensor 306.

FIGS. 7 and 8 illustrate a state where an inclined surface of the lever pushing member 303 located at a lower portion of the lever 203 overcomes a resilient support force of the spring 205, pushes the inclined surface of the lever 202 to the outside, and returns to the original position while the pressing plate 302 and the lever pushing member 303 are returning to their original positions after the support plate 202 and the lever 203 have returned to their initial states.

It is apparent that since rotation of the first shaft 201 is restricted by the stopper in a state where the lower unit 200 is located at its original position, the lever 203 is not rotated but pushed outward even when the lever pushing member 303 is lifted, pushing the lever 203 upward.

Hereinafter, the operation of the paper mixing preventing apparatus 100 of the present invention will be described with reference to FIG. 9.

If the upper unit 300 is driven at the initial state (FIG. 9A) of the upper unit 300 and the lower unit 200, the lever pushing member 303 presses an end of the lever 203 and rotates the support plate 202 (FIGS. 9B and 9C).

If the lever pushing member 303 of the upper unit 300 is rotated by a predetermined angle, the contact between the lever pushing member 303 and the lever 203 is released and the lower unit 200 returns to its original position (FIG. 9D). The lever pushing member 303 pushes only the lever 203 outward so that the upper unit 300 cannot influence the initial state of the lower unit 200 while it is returning to its original position after the lower unit 300 has returned to its original position (FIG. 9E). If the lever pushing member 303 is reversely rotated further from the state shown in FIG. 9E, the upper unit 300 returns to its initial state as shown in FIGS. 1 and 2.

Hereinafter, a paper stacking process through the paper mixing preventing apparatus 100 will be described in detail with reference to FIGS. 11A to 11E.

Next, a paper stacking process through the paper mixing preventing apparatus 100 will be described in detail with reference to FIGS. 11A to 11E.

First, the first paper sheet 600 is fed between the pressing plate 302 of the upper unit 300 and the support plate 202 of the lower unit 200 through the spacing between the rollers 502 as in FIG. 11A from the initial states of the upper unit 300 and the lower unit 200, and a rear end of the first paper sheet 600 is detected by the paper detecting sensor 503.

Thereafter, as illustrated in FIG. 11B, the upper unit 200 is driven such that the rear end of the paper sheet 600 can be pressed by the pressing plate 302 when the rear end of the paper sheet 600 reaches the support plate 202. In the process of driving the upper unit 300 and rotating the pressing plate 302, the lever pushing member 303 pushes the upper end of the lever 203 and the support plate 202 is rotated downward toward the stacker tray 400. That is, when the rear end of the paper sheet 600 passes by the support plate 202 on the feeding path in the process of feeding the paper sheet 600, the support plate 202 is rotated to avoid contact with the rear end of the paper sheet 600. As described above, since the support plate 202 is rotated without interfering with the paper sheet when the rear end of the paper sheet 600 passes through the support plate 202, the pressing plate 302 smoothly presses the rear end of the paper sheet 600 and the rear end of the paper sheet 600 is located behind an end of the support plate 202 with respect to the initial state of the lower unit 200 when the paper sheet 600 is located on the stacker tray 400.

Thereafter, the pressing plate 302 is rotated to a position detected by the pressing plate position detecting sensor 306 as in FIG. 11C, the contact between the lever pushing member 303 and the lever 203 is released. Then, the lower unit 200 returns to its original position, and the first paper sheet 600 is completely stacked on the stacker tray 400.

After the first paper sheet 600 is stacked, the upper unit 300 returns to its original position as in FIG. 11D.

After the upper unit 300 returns to its original position, the second paper sheet 601 is fed as in FIG. 11E, and is then stacked on the stacker tray 400 through the processes of FIGS. 11B to 11D.

As described above, according to the present invention, the support plate 202 remains on the feeding path of a paper sheet while the paper sheet is being fed, and is rotated and moved downward in association with the pressing plate 302 pressing an end of the paper sheet when an end of the paper sheet passes through the support plate 202.

Thus, when a tip end of the succeeding paper sheet proceeds toward the support plate 202, since a rear end of the paper sheet which has been completely located on the stacker tray 400 is located behind the tip end of the support plate 202, the stacked paper sheet and the succeeding paper sheet are prevented from being out of sequence.

Although a preferred embodiment of the present invention has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. 

1. A paper mixing preventing apparatus comprising: a lower unit including a first shaft, a support plate fixed to the first shaft, and a lever supported by at least one end of the first shaft and configured to move in association with a rotation direction of the first shaft; and an upper unit including a second shaft installed parallel to the first shaft, a pressing plate fixed to the second shaft and disposed on a side facing the support plate of the lower unit, and a lever pushing member installed in the pressing plate, wherein the support plate of the lower unit is rotated about the first shaft by a predetermined angle by a contact between the lever pushing member and the lever when the pressing plate of the upper unit is rotated about the second shaft, and wherein the contact between the lever of the lower unit and the lever pushing member of the upper unit is released if the pressing plate of the upper unit is rotated by more than a predetermined angle so that the upper unit returns to an initial state thereof after the lower unit primarily returns to an initial state thereof.
 2. The paper mixing preventing apparatus of claim 1, wherein one of a paper buffering unit, a paper arranging unit, and a stacker tray is installed under the lower unit.
 3. The paper mixing preventing apparatus of claim 1, wherein the lever of the lower unit is movably supported in a central axis direction of the first shaft, and the lever pushing member makes contact with a side surface of the lever of the lower unit and returns to an initial state thereof while pushing the side surface of the lever when the upper unit returns to an initial state thereof.
 4. The paper mixing preventing apparatus of claim 3, wherein the lever pushing member and the side surface of the lever are inclined with respect to each other.
 5. The paper mixing preventing apparatus of claim 4, wherein a lower surface of the lever pushing member makes contact with an upper surface of the lever when the lever pushing member is located at an upper portion of the lever, and the inclined surface of the lever pushing member and the inclined surface of the lever make contact with each other when the lever pushing member is located at a lower portion of the lever.
 6. The paper mixing preventing apparatus of claim 3, wherein the lever is resiliently supported by a resilient member so as to be movable in a central axis direction of the first axis.
 7. The paper mixing preventing apparatus of claim 3, wherein a paper detecting sensor is installed on a rear side of the lower unit to detect a paper sheet being fed, the upper unit is driven by a signal of the paper detecting sensor, the pressing plate of the upper unit presses a rear end of the paper sheet being fed and the support plate of the lower unit is rotated in association with the pressing operation of the pressing plate so as not to interfere with the pressing operation of the pressing plate with respect to the rear end of the paper sheet.
 8. The paper mixing preventing apparatus of claim 1, wherein the lower unit returns to an initial state by a resilient member.
 9. The paper mixing preventing apparatus of claim 6, wherein the resilient member is a spring.
 10. The paper mixing preventing apparatus of claim 8, wherein the resilient member is a spring. 